Electrical fire alarm



July 4, 1933. R.` P. JAMESON ELECTRICAL FIRE ALARM Filed Oct. 27, 1931 Patented July 4, 1933 UNITED STATES PArsN'r erica RONALD PURVIs JAiviEsoN, '0E oiinisfiioiiiiiacii, NEW ZEALAND, AssIeNoR To THE VIGILANE AUToMA'rio Erni; ALARM COMPANY LiiiiriE-D, or enmarcar-TECH, NEW

ZEALAND, A COMPANY or NEW ZEALAND vEnEcTiaioAL FIRE ALARM Application filed vCctober 27, 193]., SieriaiNo.

This invention relates to electrical fire alarm systems in which thermostatic circuit controlling devices are adapted to operate a closed circuit and an open circuit by means of a system of yieldable contacts within the circuit closing device, and particularly to the kind in which one of the yieldable contacts normally completes the closed circuit but which, upon release, will break such closed circuit and operate to close a normally open circuit. as in the pendingv application N umber 323,083 liled 1st December 1.928.

The object ot'the present invention is to v Iimprove and simplify the construction of the thermostatic circuitcontrolling device and render it moreeii'icient.V A further ob]e'c t is to enable the 'breaking of thel closed circuit Vto operate Va ltransmitting device and cause a message to be transmitted to an alarm station,

or where desired, and, at the same time, Vto enable the closing ot'l the open circuit to send a similar message by another or the same transmitter, thereby providing adouble message, but a mere fault or a failure ofone of the circuits, such as a broken line, willvonly convey a single message, thereby indicating that there is a fault in the system or only a partial operation ofthe therinostatic device.

According to the present invention, a yieldable contact is fixed at one end in a terminal post to which one liner of the closed circuit is connected. The, other end ot this yieldable Contact is such that it would normally spring away or disconnect from a. contact post'to which the other line ot' a closed circuit is connected. This yieldable contact, however,

is caused to bear tirmlyagainst its contact post by means of a rod or pin connected to the yieldable contact andpassing through the casing of the device and normally held at that position through the intervention of a fusible metal, or other suitable substanco fusible by heat. which, upon the fusing or'inclting thereof, will release the rod and permit the jyieldable contact to resume4 its normal position `under its own tension and break contact'with its contact post, thereby breaking the closed circuit; A further terminal post, insulated fromV the two nprevious posts, has the" lines of the open circuit connected thereto and-this post contains a yieldable Contact which extends to a position where it will normally liV between the end ofthe closed circuit yieldable Contact and a fixed contact projecting from a 571,389, and in New Zealand July 10, 1931.

post metallically connected with the contact post of the closed circuit.

The invention will be described with the aid Figure l, is a cross sectional elevation ure l,- the cut being along line A-A F igure l. Y Y

Figure 3, is a sectional plan ot the portion carrying the contacts and taken along line B -l'7 Figure 2.V l

Fure 4, .is a side view of a detail. Fig i 5, is Va sectional elevation through the rod and fusible nuts, but drawn to a scale r twice that of the'previous gures.

lFigure 6, is a cross section on line `C-C,

`Figure 5. n p A Referring to the drawing, a. base l, preferably of a suitable electrical insulating material, has depending from ita flange or wall 2, a central opening 3 in the base being screw.V

threaded upon theend ot conduit tubing l.

[in opening 5 in the wall 2 is provided to permit the wiring vto passte the lett or rearv side of the Wall 2,'which is strengthened in ,izts attachment to the'base l by buttress pieces 8 to which one lineot the closed circuit would be connected. ln this post, a yieldable contact consisting of a metallic metal'strip 9 is fixed and is suoli that its other end would normally sprin 0' awayfrom a contact 10 mount-ff ed in a contact fork ll iixed'in the wall 2v, t which fork the other line of the closed circuit is connected by its terminal screw 12. Y Y

Another terminal post-'13 is mounted inthe wall 2 and insulated from the post 8 by reason vof the material oi the wall. This post carries a yieldable Contact formed ot a strip of metalV ll/ounted on the wall12 is a terminalpost lfl whicheXtends to a position where it will normally lie'between the ends 'ofthe closed circuit yieldable Contact 9 and a Contact piece l5 carriedin the Contact forli l1. i The lines of the open 'circuit Vare attachedto the terminal sci-owl@ oithe post i3. ."lhe yieldable contact 9 is caused to .bear firmly against'its Contact post 10 (see Figures' and 5).-by

means ot a rod orY pin 18 connected to the yieldable contact .by passing through fa slot 19 therein having a 2 washer 2l interposed between the pin and the contact. T liislrod passes through a Vguide sleeve 22 adjustably l bearing againstV a threaded into a postI 24 fixed in the wall 2. rIhis retaining rod is held in an adjusted position by a double-nut consisting of an inner nut 25 screwed on the threaded `end of the retaining rod 18. l

hollow shell 26 forms the external part of,

the double nut and is adhered lto the inner nut 25 by having a space 27 between the two nuts filled with a fusible metal in order to adhere the two parts together, the edge of this outer nut or shell bearing on the sleeve f 22. By rotatingthe nut, the contact 9 is .tension of the yieldable contact 9, will draw the inner nut into the space 28 in the sleeve 22.

The` outer end of the nut may be flared, as shown in Figure 5, and the interior of the shell 26 formed slightly larger at its inner l end .than at its outer end.

When the fusing takesv place, and the retaininU rodv 18 is released as above described lthe yieldable contact 9 will move away from the contact 10, and will at first break the normally Closed circuit existing between the fork 11 and the terminal 8 through wires 28 and 29 and will contact with the yieldable vcontactl: and complete the normally open Y circuit from wire 28 through the contacts' 9 and 14 to the terminal post 13, to which an open circuit line 30 is connected.

The release of the closed circuit cont-act 9,

rwhen sufficiently free by the fusingof the lmetal, in the space 2"?, will also move the sec- .ond contact 14 and cause it to Contact with the contact piece 15 of the fork 11 and again bridge the-lines of the closed circuit-between the post 8 and the forli 11 yto which the wire 29 is connected, thus again causing the latter circuit to function. Also, when the contact .14 makes contact with the contact piece 15, a

.further open circuit is completed fromy wirey .29 through strip 14 toa wire 32, also attached to terminal screw 16 of thepost 13, thus providing two alternative paths for the open circuit, rone path being through the wire 28, oost 8, strip 9, strip 11i, post 18 and wire 30,

while the otherppath is through wire 29, post 11, strip 14,post 13 and wire 82. rlwo con-v tact ponts 31 and 82 on the strips 9 and 14 ensure a good contact between the strips 9 and 14C;

o .As in the previous devices using this form of circuit, the opening ofv the closed circuit maygive preliminary alarms, and by the closing of the open circuit by tie bringing tov gether of the two yieldable contacts 9 and 14,

va'transmitting device maybe operated for sending a signal-to a firebrigadc statiomfand the Treinalring of the closed circuit puts the fire' `alarm system again intoV actionffor the c remaining thermostats in the same lines.

What I claim is 1. In electrical lire alarm systems, a therinostatic switch device including a rigid part, a yieldable contact and other contacts associated therewith, a member controlling'k said yieldable contact, adjustable retaining 4means upon the end of said member to adjust said yieldable contact and held against the rigid art of the device, said retaining means formed of two parts, one part prevented from inward movement by the .rigid part of the device, the other part Vadjustably joined to said member, fusible metal interposed between the two parts, said other part moving in relation to the first part and permitting said member to move inward under tension of the yieldable contact when the fusible'metal is fused due to heating.

2. In electrical fire alarm systems, a therinostatic switch device including a` casing,l

a yieldable contact and other contacts associ- Y ated therewith,`a sleeve fixed inthe casing of the device and rigid therewith, amember consistingiofr a rod pivotally attached at one end to the yieldable rcontact and kguided in said sleeve, two-part retaining means adjustable on the end of said rod, fusible metal interposedbetween the two parts of the retaining `means, one part of said retaining meansbearing against theend of said sleeve, andl the otherpart threadably connected to said rod and free tomove in relation to the first-part under tension' ofthe yieldableV contact upon the fusing of the fusible metal interposed between the two parts of the retaining means.

3. In electrical fire alarm systems, a thermostatic switch device including a casing having a rigid part, ayieldable contact and other contacts associated therewith, a member connected at one end to said yieldable contact, a nut screwed rupon t-he other. end of said member, said nut formed of two parts,y a fusible metal holding the nut parts together, one part held against a rigid part of the casing and the other part free to move inwardly iin-.E

der tension of the yieldable contact upon the fusing of i themetal retaining the two" parts of the nut together. Y

4. In the thermostatic device as claimed in claim 10, al sleevefixed in the .casing of ,the`

device, said member in the formof a rod piv- -otally attached, at one end to the yieldable Contact and passing through said sleeve, one part of said nut formed of an inner nut screwed upon other part of said nut formed of an outer shell and held to the first part by the fusible metal and bearing upon the end of the sleeve, said inner nutfree to move through the outer shell under tension of the yieldable contact.

upon the fusing'of the metal retaining-the two parts of the nut together. i *f v if Inv testimony whereof, I'have signed my name to this specification. y i f RONALD PURVIS JAMESON.-

the other endof said rod, the 

